If shooters are exposed to gunfire noise for a very short duration, then why is the noise level so critical?
A. Shooting outdoors is not as critical due to the absence of reflective surfaces for gunfire impulse noise levels. When the shooters are exposed to the same impulse noise levels in an indoor facility the untreated reflective surfaces increase the impulse noise levels. Impulse noise is a sharp sound level peak occurring in a short time interval. OSHA & NIOSH regulations state the impulse noise exposure limit is 140dB peak or 100 impulses for an 8-hour period. The OSHA & NIOSH noise regulations state that the 140 dB should not be exceeded; OSHA does not enforce this limit. The limit is based upon the assumption that there is a critical level, a level above which there is high risk, no matter how short the duration might be. John Franks, NIOSH noise expert, has defined regular exposure to 85dBA as one day or more a month unless a worker is exposed to over 110dBA for any length of time in which case the dose does not matter. According to Franks, workers such as firefighters, medical emerg
